1. Field of the Invention (Technical Field)
The present invention relates generally to systems for providing meteorological information, particularly to apparatuses for supplying weather data to aircraft pilots, and specifically to a receiver and calculator apparatus for simultaneously receiving, processing, and displaying weather and other data to pilots of private aircraft.
2. Background Art
Historically, pilots of private aircraft have relied on a wind sock viewed from 1,000 to 1,500 feet while flying over a private airfield or heliport to determine wind speed and direction. More recently, in airports having tower operations or a fixed base operator, aircraft pilots have used radio voice communication with operators at the airport to obtain important weather information, including wind speed and direction. Within the last fifteen years at public airports in the United States, the federal government has installed automated weather observation systems (AWOS). AWOS measure airport weather conditions, and then broadcast periodically updated voice recordings to transmit the information to aircraft near the airport. This system was recently upgraded to a more sophisticated Automated Surface Observing System (ASOS) at the 1,000 largest public U.S. airports. The ASOS system provides a variety of weather information via voice radio communication to aircraft in the vicinity of the airport. Such automated systems can cost anywhere from $30,000 to $150,000 per airport. Both AWOS and ASOS require aircraft pilots to process audible (voice message) information from a radio receiver in the aircraft. There are about 5500 public airports in the United States that should 1 have automatic weather systems provided by the federal and local government to facilitate air safety for public air transportation. However, there are an additional 13,200 private airstrips, heliports, and seaplane bases that, due to cost constraints, will not be instrumented via these federal programs. There is a need, therefore, for a low cost, reliable, alternative system.
Meteorological information is important, of course, to pilots of small aircraft. Such weather factors as crosswind and headwind speed and direction, wind gust speed and direction, and dew point temperature inform the pilot""s judgment, particularly during takeoff and landing. The pilot operating out of a small private airport may, at best, obtain some basic absolute wind speed and direction, barometric pressure, and temperature information from automated audio broadcasts from the facility, or from live audio radio communication from the fixed-base facility operator. At numerous remote airstrips, the pilot must still rely upon a wind sock, or upon regional weather reports. Still, even voice communications from a fixed base operator or automated broadcast leave the pilot with the task of referring to printed graphs, charts, and nomographs, and operating hand-held standard electronic calculators, or maybe even performing handwritten calculations, to determine from raw audio data such other vital information as cross wind and headwind speeds and directions, dew point temperature, and the like. Still further, the pilot should use the meteorological information thus determined to evaluate whether a takeoff or landing can be safely performed in his particular type of aircraft, under the given weather conditions, on a particular runway. Performing the task correctly is important, and desirably is not undertaken simultaneously with flying the aircraft and listening to the radio. Even when an assistant is available to perform the calculations, the opportunity for human error suggests the desirability of an apparatus which simplifies the task and minimizes error. A need remains, therefore, for a system and apparatus for receiving raw meteorological data and calculating therefrom additional derived meteorological and related information useable by a pilot, without the pilot having to be distracted while operating the aircraft itself. Against this background, the present invention was developed.
The invention relates to an apparatus for assisting pilots and others in easily and rapidly obtaining accurate raw and calculated meteorological data for use in making judgments in the course of flying an airplane, helicopter, or other aircraft. Broadly described, the invention is a receiver-calculator unit, useable in combination with a ground-based weather station transmitter. The unit preferably is portable, so that it can be removably placed in an aircraft, or be hand-held outside the aircraft, or be moved from aircraft to aircraft. Disposed within the unit housing are signal receiver components and electronic calculation components of generally known construction. A central processing unit in the unit permits the processing of data transmitted from the ground-based station to calculate additional useful derived meteorological information for viewing upon a unit display.
The ground-based transmitter obtains raw meteorological data from various measurement devices on the station, and also may be programmed to transmit certain site-specific physical data, such as runway length, runway altitude, and other information useful to a pilot""s decision making. The transmitter transmits signals conveying the raw data concerning meteorological conditions at the ground-based station, as well as site-specific information, to a signal receiver disposed inside the unit housing. Digitized raw meteorological data is then transferred electrically from the receiver to the central processing unit, which calculates derived meteorological information at least in part from the raw meteorological data accepted from the signal receiver. The invention also includes some means for the operator to manually input into the CPU site-specific physical data of interest. In the case of airstrips, this physical data usually and preferably includes information about the runway, most particularly the heading (directional layout with respect to north) of the runway, or runway altitude or runway length. The site-specific physical data, such as runway heading, is a variable that also may be manipulated within the CPU to generate derived meteorological information.
The invention preferably includes at least some digital memory for storing both raw and input data as well as derived data. The memory is in communication with the CPU, so that data may be placed into and retrieved from memory by the CPU according to known digital calculation processes. Raw meteorological data from the receiver may be sent straight through for viewing upon the display on the unit, and/or may be sent to storage memory for later recall and processing. Likewise, physical data input from the data input may be stored for later processing in the CPU.
A primary object of the present invention is to provide an economical system and apparatus, useable at small, isolated, unstaffed, or private airports, for readily providing pilots with very local meteorological data and information.
A primary advantage of the present invention is that it can be economically manufactured.
Another advantage of the invention is that it frees a pilot flying an aircraft from having simultaneously to listen to audio weather broadcasts, if they are even available, and from having to fumble with charts, slide rules, conventional arithmetic calculators, and pencils and paper, in order to obtain weather data for use in flying the aircraft or making pre-flight decisions.
Accordingly, there is provided in accordance with the invention an apparatus useable in combination with a ground-based weather station, the station transmitting signals conveying raw data concerning meteorological conditions at the station, the apparatus comprising a signal receiver for receiving the transmitted signals, a central processing unit for calculating derived meteorological information at least in part from the raw meteorological data accepted from the signal receiver, and means for displaying the raw meteorological data and the derived meteorological information. Preferably, site-specific physical data also is conveyed from the ground-based station to the signal receiver. Preferably, the signal receiver comprises a radio receiver. The raw meteorological data may comprise one or more members selected from the group consisting of temperature, relative humidity, average wind speed, average wind direction, wind gust speed, and wind gust direction, while the derived meteorological information comprises at least one member selected from the group consisting of density altitude and dew point temperature. When the ground-based station is at an airport runway, there is provided some means for inputting into the central processing unit site-specific physical data regarding the runway, such as runway heading, altitude, and length. In alternative embodiments, there maybe means for inputting data concerning aircraft performance characteristics particular to the aircraft in use. When the ground-based station is at a golf course, there is provided some means for inputting into the central processing unit physical data respecting a fairway, and the derived meteorological information further comprises crosswind speed. At airports, the derived meteorological information may comprise crosswind speed and/or headwind speed. The means for displaying data comprises at least one member selected from the group consisting of light-emitting diodes and liquid-crystal displays.